Wound electrical device and method of making it



V. G. APPLE March 17, 1931.

WO UND ELECTRICAL DEVICE AND METHOD OF MAKING IT Filed March 1, 1928 AITORNEY Patented Mar. 17, 1931 vmcmr'r G. APPLE, QF DAYTON, OHIO WOUND ELECTRICAL DEVICE AND METHOD OF MAKING. IT

Application filed March 1, 1928. Serial No. 258,398.

My invention relates to improvements in the structure of wound electrical devices and V in the method of retaining the windings thereon.

One of the objects of my invention is to provide a structure wherein the winding and the connection between the winding and the terminals and the terminals themselves, all are imbedded in a mass of insulating material, which cements the winding to the core and keeps it rigid, to the end that deterioration incident to vibration of the parts, where yielding windings and flexible leads are employed, will be eliminated. v Another object is to so enclose the conducting elements of the structure as to effectually protect them against deterioration from the action of oil, moisture, corrosive gases, etc., to which wound electrical devices of the conzo ventional type are subject.

Still another object is to eliminate the frame usually required in wound electrical devices .by forming a frame out of the same 7 3 mass of insulating material within which the ll winding is imbedded.

Still another object is tosecure attaching means for the device and terminals for the winding to the body of the structure in such a manner that they will materially strengthen the structure by tying the insulation mass to the body which carries the winding.

Still another object is to provide a simple and efiicient method of procedure. to carry the other objects into effect.

I attain all the foregoing objects by the structure and method hereinafter described, reference being had to the drawing wherem.

Fig. 1 is a longitudinal cross section thru an electro-magnet made according to my invention. v

Fig. 2 is a longitudinal cross section thru the impregnating mold used in making the electro-magnet Fig. 1.

Fig. 3 is a longitudinal cross section thru a second mold for adding heavier masses of insulation.

' Fig. 4 is a cross section thru a transformer built by my method. a

Fig. 5 is a cross section thru another elec tromagnet built by my method.

Similar numerals refer to similar parts thruout the several views.

The conventional Wound, electrical device usually comprises one or more coils wound about a core, or other member adapted to carry the winding, the coils bein dipped or otherwise impregnated with liqui insulation and baked to make a rigid structure, together with a frame or casing, separately made, to which the wound and impregnated structure may be secured, the terminals for the winding usually being mounted in the frame or casing and loose ends of the coils usually being connected to the terminals.

The present invention consists, in part, in adding to the mass of insulation which impregnates the windings so as to form a cas ing thereof, which will enclose the coils so that no other frame or casing is needed, the terminals, the coils, the connections therebetween, the attaching bolts, etc., all being imbedded in the same substantially continuous mass of insulation, so as to electrically, mechanically and chemically protect the several parts of the structure.

To illustrate my invention Figs. 1, 2 and 3 show an electro-magnet and the method employed to produce it. A magnetizable core 10, having upwardly extending poles 11 and laterally extending ends 12 is provided. Bushings 13 of insulating material are driven into holes in ends 12 and terminal posts 14 are driven into bushings 13. Coils 15 are placed over poles 11 and the ends of the wire composing the coils are joined to terminal posts 14 at 16. Attaching studs 17 are entered into suitably positioned holes in ends 12 all substantially as shown, and the structure is read to have the insulation mass applied. a

W ere, as in the instant case, the structure is such that the insulation mass is considerabl in excess of that required to cover the coi s, and is preferably of considerable strength, insulation in two forms is usually employed and molded in two separate operations, a, different mold being provided for each operation. This molding procedure is fully described in my co-pending application Serial No. 205,253 and consists briefly of using insulation of considerable fluidity, which may not be readily cured in large masses, for the first operation, to impregnate the winding, to cement it to the core, and to slightly cover the coils and the joints between the coils and the terminals, so that afterward plastic molding compounds of lesser fluidity containing fibrous fillers to increase their strength may be safely used and molded to the struc ture in the greater masses required.

Where, however, the extent and the nature of the insulation required permits molding a single kind of insulation to the finished form in a single operation, the molding is preferably carried out in that manner.

Fig. 2 shows the impregnating mold comprising parts 18 and 19 held together by bolts 20, the wound structure being contained therein. A very slight space 21 is permitted in the mold around the coils 15 and around the joints 16 between the coils and the terminals, and around a small portion of attaching studs 17 Pipes 22 areheld in place by pressing flanges 23 against the mold until the winding is impregnated, when they may be quickly withdrawn and solid plugs substituted in their stead. A Vacuum process may be employed wherein one pipe 22 exhausts the air from the inside of the mold and from the interstices of the winding and the other sub sequently permits the liquid insulation to be drawn into the mold, or the liquid may, be

poured or pumped in thru one pipe and the other used for a vent until the mold is filled. In either event when the mold is filled, the entire structure, including the mold, core, Winding, terminals and attaching screws are baked until the liquid insulation becomes a solid mass, after which the mold is removed.

The structure is then placed in mold Fig. 3 which is made in two parts 24 and 25 and has a vertically movable plunger 26 in part 24. Since the coils and the joint between the coils and terminals have previously been covered with a hard coating of insulating material in mold Fig. 2, no damage to the structure results when plunger 26 is raised and a quantity of loose molding compound is placed under it and forced downward by heat and pressure, by the well known molding process, to fill open spaces 27. and 28 to provide a housing 29 and a base 30 of the insulating material.

Fig. 1 shows the completed electro-magnet encased in the housing of insulation, and whether the insulation has been added to the structure by the two operation process 'described or b a single operation, it is apparent that w1th the terminals 14 fastened to the core andthen imbedded in the insulation mass, and the attaching studs extending thru and beyond the core andinto the insulation at both ends, and the coils surrounde by a suitably shaped casing of the insulation as shown, all of the objects here-. inbefore set forth have been attained. The

terminals 14 extend from the insulation for connection to the external circuit and the carrying coils 41 and 42, incandescent lamp.

terminals 43 and 44 for primary coil 41, lamp socket terminals 45 and 46 for secondary coil 42, and a casing of insulation 47 molded in situ to penetrate, surround and support the several parts of the device. The terminals 43, 44, 45 and 46 are attached to the core. by bolts 48 which pass thru insulation bushings 49, saidbushings also extending thru the terminals to keep one pair of terminals insulated from the other. The coils are joined to the terminals at theirpoints of support on the core as at 50 and 51 so that slight deflection of the terminals during the molding operation'will not sever the wire therefrom. The insulation may be applied in one or more operations depending on the nature of the insulation used. The device is adapted to be inserted into a ,lamp socket to draw-current for the primary coil and to have a plug inserted at its lower end for taking current of other voltage from the secondary, though it is obvious that the terminals at either end may be formed at the surface ofthe insulation mass, into binding posts, slip connections, or whatever form of connector is desired.

Fig. 5 is a cross section thru an electro magnet comprising, a core 60, a coil 61, a grounded terminal 62, an insulated terminal 63, and a cover of insulation 64 surrounding the core, coils, and terminals to protect and bind the structure together.

Terminal 62 is pressed directly into a hole in the core, while terminal 63 is pressed into an insulation bushing 65 which is pressed into the core. The coil may be wound in place and its ends joined to the terminals, then/the insulation molded in place to further fix the terminals as well as the other parts of the structure. Since the structure shown in Fig. 5 does not require large masses of insulating material of great strength, the insulation is preferably applied in a single operation.

While the drawing and description show and describe relatively few embodiments of my invention, it is readily conceivable that the principles involved may be advantageously applied in producing wound electrical devices of almost any character, and while the several structures shown all embody a core of magnetic material it is obvious that the coils may be wound on a hollow member of non-magnetic metal or of insulating material, terminals attached thereto, and the mass. of insulation molded thereabout, and

a magnetizable core afterward separately inserted into the hollow member.

Having described my invention, I aim to more fully define its scope in the following, wherein I claim 1. An electrical device ber adapted to carry a winding, a winding on said member, terminals for said winding supported on said member, said winding being jointed to said terminals, and asubstantially continuous mass of insulating material impregnatingv and covering said winding "and covering the joints between said winding and said terminals.

2. An electrical device comprising a member adapted to carry a winding, a winding on said member, terminals for said winding mechanically joined to said member, but electrically insulated therefrom, said winding comprising a mem- -being electrically joined to said terminals,

and a substantially continuous mass of insulating material impregnating and covering said winding and covering the joints between said winding and said terminals.

3. An electrical device comprising a member adapted to carry a winding, a Winding on said member, terminals for said winding supported on said member, said winding being electrically joined to said terminals, and a substantially continuous mass of insulating material impregnating and covering, said winding, covering the joints between said winding and said terminals, and cementing said winding to saidv member.

4. An electrical device comprising a member adapted to' carr a winding, a winding on said member, terminals for said winding supported on said member, said winding being electrically joined to said terminals, and molded insulating material impregnating and covering said winding, covering the joints between said nals, cementing said winding to said memterminals.

5. In an electrical device, a core, a winding on said core, attached to said core, lated therefrom, joints and said terminals, molded thru and about but electrically insu between said winding insulating material said core, winding,

terminals and joints to prevent. relative.

movement between said parts to injure said joints, and to imbed and further secure said terminals.

6. A wound electrical devicecomprising a member adapted to carry a winding, a winding on said member, relatively heavy terminals for said winding rigidly aflixed to said member, the ends of said winding being joined to said terminals, and a mass of insulation extending thru and about molded the winding and terminals, the free ends of c said terminals extending to the surface of winding and said termimy name. ber, and furnishing further support for said terminals for said winding the insulation mass and there being formed e the terminals of an incandescent lamp, so that the current may be applied to said winding by entering said terminals into a lamp socket.

7. An electrical device comprising a member adapted to carry a Winding, a winding on said member, a terminal for said winding secured to said member, electrically joined to said terminal near its point of support on said member, and a substantially continuous mass of insulating masaid winding being terial covering said winding and the joint v mass of molded insulation covering said winding and extending further to form a frame for said device, and attaching means for joining said device and other structures together, said attaching means extending from said core thru and be yond said frame, and being roughened where it passes thru said frame to assist in tying said frame to said core.

10. An electrical device comprising a core, a winding on said core, a mass of molded insulation covering said winding, and a terminal for said winding and extending thru said insulation mass to the surface thereof to convey current for said winding and to tie said insulation mass to said core.

\ In testimony whereof I hereunto subscribe VINCENT er.- APPLE.

thru said insulating attached to said core 

